End functionalized polymers, such as end functionalized polyisobutylenes, are useful as modifiers in oleaginous compositions, as well as being important starting materials for preparation of useful materials such as polyurethanes and amphiphilic networks. Typically functionalized polymers, such as functionalized polyisobutylenes, are prepared by multistep processes that require isolation of the polymer in at least two steps. However, multistep processes are commercially undesirable.
With the advent of carbocationic living polymerization, there have been attempts to functionalize the living polymers. The extent of success of these attempts are directly linked to the type of monomer being polymerized. Simple one-pot (or in-situ) chain end functionalization of more reactive carbocationic monomers, like isobutyl vinyl ether, can occur using ionic nucleophilic additives, i.e. methanol, alkyl lithium, etc. (see M. Sawamoto, et al. Macromolecules, 20, 1 (1987).) However, chain end functionalization does not occur when these additives are added to the living polymerization of less reactive monomers such as isobutylene. (see Z. Fodor, et al, Polym. Prepr. Amer. Chem. Soc., 35(2), 492 (1994).) Addition of these reagents at the end of isobutylene polymerization resulted in the consumption of the catalyst and the formation of t-alkyl chloride chain ends on the polyisobutylene rather than the desired nucleophilic substitution. Consequently, a multi-step process would be required to functionalize a living polymer from these less reactive monomers. Even when one considers that allylic chain ends can be provided by an in-situ functionalization of living polyisobutylene by adding allyltrimethylsilanes at the end of polymerization, (see EPA 0 264 214 or B. Ivan, et al, J. Polym. Sci., Part A, Polym. Chem., 28, 89 (1990) this functionalization limits the choice of chemistries to introduce functional groups, however. Thus, there is a need in the art to provide single and two or three step processes to provide functionalized living polymers comprising less reactive cationic monomers, such as isobutylene.
Electrophilic displacement reactions have thus far not been considered a viable option with living polymers since it is thought that the concentration of active chain ends is too small for further reaction. While such displacements have been carried out with non-polymeric halides, such as 1-adamantyl, there is no indication that such displacements will be successful with living polymers, such as polyisobutylene.